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of 103
pro vyhledávání: '"Daneshkhah, Ashraf"'
In this article, we investigate symmetric designs admitting a flag-transitive and point-primitive affine automorphism group. We prove that if an automorphism group $G$ of a symmetric $(v,k,\lambda)$ design with $\lambda$ prime is point-primitive of a
Externí odkaz:
http://arxiv.org/abs/2409.04790
Autor:
Alavi, Seyed Hassan, Amarra, Carmen, Daneshkhah, Ashraf, Devillers, Alice, Praeger, Cheryl E.
It was shown in 1989 by Delandtsheer and Doyen that, for a $2$-design with $v$ points and block size $k$, a block-transitive group of automorphisms can be point-imprimitive (that is, leave invariant a nontrivial partition of the point set) only if $v
Externí odkaz:
http://arxiv.org/abs/2404.11241
Autor:
Daneshkhah, Ashraf
In this article, we prove that if $\mathcal{D}$ is a $2$-design with $k=7$ admitting flag-transitive almost simple automorphism group with socle an alternating group, then $\mathcal{D}$ is $PG_{2}(3,2)$ with parameter set $(15,7,3)$ and $G=A_7$, or $
Externí odkaz:
http://arxiv.org/abs/2307.05190
In this article, we study symmetric designs admitting flag-transitive, point-imprimitive almost simple automorphism groups with socle sporadic simple groups. As a corollary, we present a classification of symmetric designs admitting flag-transitive a
Externí odkaz:
http://arxiv.org/abs/2307.05184
The main aim of this article is to study the quantitative structure of projective symplectic groups $PSp_{4}(q)$ with $q>2$ even. Indeed, we prove that the groups $PSp_{4}(q)$ with $q>2$ even are uniquely determined by their orders and the set of the
Externí odkaz:
http://arxiv.org/abs/2208.13263
Autor:
Alavi, Seyed Hassan, Bayat, Mohsen, Biliotti, Mauro, Daneshkhah, Ashraf, Francot, Eliana, Guan, Haiyan, Montinaro, Alessandro, Mouseli, Fatemeh, Rizzo, Pierluigi, Tian, Delu, Wang, Yajie, Zhan, Xiaoqin, Zhang, Yongli, Zhou, Shenglin, Zhu, Yan
In this paper, we present a classification of $2$-designs with $\gcd(r,\lambda)=1$ admitting flag-transitive automorphism groups. If $G$ is a flag-transitive automorphism group of a non-trivial $2$-design $\mathcal{D}$ with $\gcd(r,\lambda)=1$, then
Externí odkaz:
http://arxiv.org/abs/2204.02439
We study point-block incidence structures $(\mathcal{P},\mathcal{B})$ for which the point set $\mathcal{P}$ is an $m\times n$ grid. Cameron and the fourth author showed that each block $B$ may be viewed as a subgraph of a complete bipartite graph $\m
Externí odkaz:
http://arxiv.org/abs/2201.01143
Publikováno v:
In Journal of Combinatorial Theory, Series A August 2024 206
In this paper, we first study biplanes $\mathcal{D}$ with parameters $(v,k,2)$, where the block size $k\in\{13,16\}$. These are the smallest parameter values for which a classification is not available. We show that if $k=13$, then either $\mathcal{D
Externí odkaz:
http://arxiv.org/abs/2004.04535
In this article, we investigate symmetric $(v,k,\lambda)$ designs $\mathcal{D}$ with $\lambda$ prime admitting flag-transitive and point-primitive automorphism groups $G$. We prove that if $G$ is an almost simple group with socle a finite simple grou
Externí odkaz:
http://arxiv.org/abs/2002.04948